The presently claimed invention relates to emissive structures and related systems.
Conventional tungsten filament lamps exhibit low luminous efficacy (˜17 lm/W for a 120 V, 750 h, 100 W lamp) compared to plasma discharge or fluorescent lighting sources. In tungsten incandescent lamps only 5-10% of radiation is emitted in the visible spectral range (390-750 nanometers), while most is emitted in the IR spectrum and is lost as heat. The rest is emitted as thermal infrared radiation, primarily in the 750-4000 nanometers spectral range. The efficiency of the incandescent lamp can be improved by simultaneous enhancement of the visible radiation emitted and suppression of the infrared radiation emitted.
Photonic lattices have been proposed as a means to prevent IR loss. These structures, in one example, are simply a periodic arrangement of two materials with different dielectric constants, e.g. tungsten and air. Periodic photonic lattices have a unique property: radiation of specific wavelengths cannot propagate through the lattice. Enhanced efficiency in visible wavelengths can be achieved if the photonic lattice is configured to increase visible absorption and/or suppress IR emission. Unfortunately, many of the photonic lattices are limited to low temperature operation (less than 1000 degrees K) due to thermal instabilities.
Therefore, it would be advantageous to develop stabilized high temperature emitters with tailored emission properties.